OBJECTIVE: The aim of this study was to assess general practitioners' (GP) readiness to involve obese patients in therapy decision making and to determine whether they integrate motivational interviewing techniques. METHODS: Fifty-eight preventive Check-up 35 encounters with overweight and obese patients in primary care were audio recorded in 12 GP practices. The use of motivational interviewing techniques was rated with the Behavior Change Counseling Index (BECCI). The involvement in medical decisions was rated with the Observing Patient Involvement Scale (OPTION). RESULTS: OPTION and BECCI scores were low (means=0.71 and 1.65), indicating minimal implementation of shared decision making and motivational interviewing in preventive encounters with these patients. GPs used more motivational interviewing for patients with a BMI>30kg/m(2) than for those with a BMI<30kg/m(2). Female GPs had significantly higher shared decision making scores, indicating that they prefer to involve patients in medical decisions. GPs differed significantly in their use of both approaches. CONCLUSIONS: Shared decision making and motivational interviewing, though known to be successful strategies in lifestyle counseling, are rarely used during obesity encounters in our sample of German GPs. PRACTICE IMPLICATIONS: GPs should be sensitized and trained in the application of these methods.